Shedding light on dark DNA Most textbook definitions of evolution state that it occurs in two stages: mutation followed by natural selection. DNA mutation is a common and continuous process, and occurs completely at random.
The average adult only eats 15 grams of fiber per day. Women need 25 grams of fiber per day, and men need 38 grams per day, according to the Institute of Medicine.
The recommended fiber intake is 20 - 35 grams per day for adults, or 10 - 13 grams for every 1,000 calories in the diet. This recommended amount should come from a combination of soluble and insoluble fiber, since each type provides different benefits. While it's not necessary to track, a 3:1 ratio of insoluble to soluble fiber is typical.